Two masons doing construction work at a demolition site in Saint-Eustache, Quebec, Canada, were confirmed to have histoplasmosis after they presented with cough and dyspnea accompanied by fever, officials from the Laurentian Regional Department of Public Health in Quebec reported in MMWR.

The first two illnesses were reported to the department of public health May 19. Other workers also were reported to be ill. A joint infectious disease, environmental health and occupational health investigation identified 14 people with respiratory symptoms among 30 who were potentially exposed at the demolition site. The investigation yielded a correlation between a histoplasmosis diagnosis and exposure to demolition dust that contained bat or bird droppings.

The 14 people with symptoms included six masons, three debris sorters, two residents, two neighbors and one site visitor. All reported dyspnea, and most reported chills, headaches, sweating, chest pain, asthenia, fever cough and myalgia. The average duration of symptoms was 12.6 days.

Two masons were hospitalized. All of the masons had worked on the demolition of a century-old brick house. Among the 14 people with respiratory symptoms who had consulted a physician, all recovered without specific histoplasmosis treatment.

The two hospitalized masons had confirmed histoplasmosis diagnosed by positive serum and positive urinary Histoplasma capsulatum antigen test. Two debris sorters also had confirmed histoplasmosis diagnosed by a urinary H. capsulatum antigen test. The remaining 26 potentially exposed people included 11 workers and 15 residents, visitors and neighbors. Five of the workers and five of the residents, visitors and neighbors received a clinical diagnosis based on symptoms.

“This outbreak highlights the importance for employers to understand the health risks associated with renovation of old houses in areas where bats or birds roost,” the officials reported. “Employers should also be made aware of the recommended health measures for their workers, such as wearing a respirator.”